<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>
  <div id="app"></div>

  <script src="node_modules/@babel/standalone/babel.js"></script>
  <script src="node_modules/react/umd/react.development.js"></script>
  <script src="node_modules/react-dom/umd/react-dom.development.js"></script>
  <script type="text/babel">
    function handleClick() {
        window.alert('666')}
    const element=(
      <button onClick={handleClick}>点我</button>
      <button onClick={()=>alert('999')}>999</button>
    )

    ReactDOM.render(element,document.getElementById('app'))
  </script>
</body>

</html>